Cha, S.-H. and Whitworth, Anthony Peter ![]() |
Abstract
Numerical simulations of the collapse of a slowly rotating cloud have been performed, assuming either isothermality, or a barotropic equation of state that reproduces the expected thermal behaviour of protostellar gas. A ring appears in the late stages of the collapse of a rotating cloud, and we have investigated the effect of differential rotation on the formation and fragmentation of this ring. In the simulations presented here, we have used Godunov-type particle hydrodynamics to avoid the side effects of artificial viscosity in a differentially rotating cloud. The initial state of a cloud is characterized by Graphic and Graphic, where Graphic, Ω and Graphic are the thermal, gravitational and rotational energies, respectively. If the initial angular velocity, ω, of a cloud is proportional to r−P, then in the isothermal simulations, a ring forms if P is larger than 0.5, provided βo≲ 0.035. In the simulations using a barotropic equation of state, with αo= 0.6 and βo≲ 0.035, a ring is always formed, irrespective of whether P≤ 0.5 or P > 0.5. However, the mechanism and time of ring formation are different in the two extremes, as are the final configurations. Strong differential rotation (P > 0.5) is more effective in inducing fragmentation than solid-body rotation (P= 0), in the sense that fragmentation tends to occur earlier and to produce more fragments when P is larger.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Physics and Astronomy |
Subjects: | Q Science > QB Astronomy |
Uncontrolled Keywords: | methods: numerical; binaries: general; stars: formation |
Publisher: | Oxford University Press |
ISSN: | 0035-8711 |
Last Modified: | 24 Oct 2022 11:14 |
URI: | https://orca.cardiff.ac.uk/id/eprint/47429 |
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